Unloading machine

ABSTRACT

This machine unloads articles piled up in layers on a pallet successively from the uppermost layer. The machine includes a movable conveyor adapted for horizontal reciprocal movement between a predetermined front position and a rear position to send out the articles rearward and an elevator for supporting articles on the pallet in the path of movement of the conveyor. The movable conveyor is provided, at its front end with a lower endless belt for scooping up the articles in frictional contact therewith and an upper endless belt disposed above the lower endless belt for preventing the articles from tumbling during scooping-up operation. These belts are driven in the direction to send out the articles rearward by a motor fixedly mounted on part of a support structure by way of chain-sprocket transmission mechanism. The upper and lower endless belts are adapted to be driven at a higher velocity when the movable conveyor is moved forward than when it is retracted.

Elite States atet [191 Yamashita UNLOADING MACHINE [75] Inventor: UmeoYamashita, Osaka, Japan [73] Assignee: Yamashita Iron Works Ltd., Osaka,

Japan 22 Filed: July 8, 1971 211 Appl.No.: 160,710

[30] Foreign Application Priority Data 3,004,650 10/1961 Pettee 198/34 A[451 July 31, 1973 Primary ExaminerGerald M. Forlenza AssistantExaminer-George F. Abraham AttorneyBruns & Jenney [57] ABSTRACT Thismachine unloads articles piled up in layers on a pallet successivelyfrom the uppermost layer. The machine includes a movable conveyoradapted for horizontal reciprocal movement between a predetermined frontposition and a rear position to send out the articles rearward and anelevator for supporting articles on the pallet in the path of movementof the conveyor. The movable conveyor is provided, at its front end witha lower endless belt for scooping up the articles in frictional contacttherewith and an upper endless belt disposed above the lower endlessbelt for preventing the articles from tumbling during scooping-upoperation. These belts are driven in the direction to send out thearticles rearward by a motor fixedly mounted on part of a supportstructure by way of chain-sprocket transmission mechanism. The upper andlower endless belts are adapted to be driven at a higher velocity whenthe movable conveyor is moved forward than when it is retracted.

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UNLOADING MACHINE BACKGROUND OF THE INVENTION The present inventionrelates to an unloading machine, more particularly to an apparatus forunloading articles piled up on a pallet in layers from the uppermostlayer one row after another and sending out the articles in a row.

An unloading machine has heretofore been known which includes a movableconveyor adapted to be moved back and forth on a plane and provided withfrictional rollers at its front end and elevator for supporting articleson a pallet in the path of movement of the conveyor so as to scoop upthe articles by the frictional rollers, deliver them onto the movableconveyor and send them out backward. However, when the articles arelifted up by the frictional rollers, the articles are frequently tumbledforward since they are brought to inclined position by the advancingrollers, with the result they are broken or scattered about. Theoccurrence of such accident consequently interrupts unloading operationto lower the work efficiency.

SUMMARY OF THE INVENTION The present invention provides an apparatuswhich is capable of unloading articles from pallets without tumbling thearticles. In connection with such apparatus, this invention provides amechanism of the novel type for scooping up articles and a drivemechanism therefor. The article scooping-up mechanism mounted on thefront end of a movable conveyor for transporting the articles backwardincludes a frictional rotary body for lifting the articles in frictionalcontact therewith and means for preventing articles from tumblingdisposed above the rotary body and adapted to hold inclined articlesfrom above. While the articles are scooped up by the rotary body ininclined position, the tumbling prevention means effectively preventsthe articles from tumbling down forwardly when the articles are pushedforward on the under faces by the advancin g frictional rotary body,thereby assuring safe unloa'ding operation. The tumbling preventionmeans comprises an upper endless belt disposed substantially in parallelwith a lower endless belt for scooping up articles in facing relationthereto and spaced apart therefrom by a distance for permitting thearticles to pass through. Both upper and lower endless belts are drivenin directions opposite to each other so as to scoop up the articles andsend out the same backward. This assures that when the upper end of anarticle is brought into contact with the upper endless belt, the upperand lower endless belts cooperate to positively send out the articletoward the movable conveyor for smooth, trouble-free and promptunloading operation. The upper and lower endless belts and rollers ofthe movable conveyor are driven by a motor fixed to a support structureby means of a chain-sprocket transmission mechanism. The provision ofthe motor on the support structures ensures the advantage that it can bemounted in place in simpler manner than is the case where it is mountedon the movable conveyor and that the movable conveyor can be driven backand forth with a lower driving force. The present invention will bedescribed in greater detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showingan unloading machine of this invention with part broken away;

FIG. 2 is a perspective view showing an elevator mechanism provided forthe unloading machine of FIG. 1, the view being a rear view of FIG. 1;

FIG. 3 is a perspective view showing only a movable conveyor mechanismin the machine shown in FIG. 1;

FIG. 4 is a perspective view showing article scooping means to bemounted on the front end of the movable conveyor of FIG. 3 and a drivemechanism therefore with part broken away;

FIG. 5 is a side elevation showing the article scooping means in FIG. 4;

FIG. 6 is a view showing the means in FIG. 5, part of the view being insection taken along the line 6-6;

FIG. 7 is a perspective view showing a stopper and a transfer assemblymounted at the rear end of the movable conveyor in FIG. 3;

FIG. 8 and 9 are views schematically showing one step of the unloadingoperation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the unloadingmachine of this invention shown in FIG. 1 is provided with a supportstructure 1 made of shape steel comprising a base frame 2 and a suitablenumber of vertical posts 3 spaced apart from each other and an uppersupport frame 4 disposed thereon. One end of a pallet feed conveyor 6supported on legs 5 extends into the lower portion of a supportstructure 1 and a number of rollers 7 are interconnected in mutualdriving relation by sprocket 8 fixed to the ends of the rollers andchains 9 reeved around the sprockets 8. One of the rollers 7 disposedintermediately of a row of the rollers 7 is operatively connected to amotor M through a sprocket and chain drive mechanism 31. When a pallet Ploaded with articles A is placed in position, the rollers 7 are drivenby the motor M so as to send the pallet P in the direction indicated bya reference arrow 10. The pallet is therefore advanced to a positionwhere it is transferred onto an elevator 11 in the machine. Disposed atthe front end of a pallet feed conveyor 6 is a photoelectric tube switchPH for giving an instruction to stop the conveyor 6 and instruction toraise the elevator 11, the arrangement being such that when the pallet Ploaded with articles A is sent to a predetermined position on theelevator 11, the front end of the pallet intercepts a beam from thephotoelectric tube switch PH As shown in greater detail in FIG. 2, theelevator 11 includes a plurality of support arms 12 each adapted to bepositioned between adjacent rollers 7, 7 of the pallet feed conveyor 6when the elevator 11 is located at the lowermost position. Each of thesupport arms 12 is secured, at its one end, to a movable frame 14 whichis adapted to be moved up and down along two vertical guide bars 13constituting part of the support structure 1 of the machine. Guiderollers 15 mounted externally on the upper and lower ends of the movableframe 14 are fitted into the groves of the guide bars 13 in verticallymovable manner. Two chains 16 for lifting the elevator 11 are passedaround sprockets 17 disposed above the upper support frame 4, one end ofeach chain being secured to the upper end of the movable frame 14 of theelevator l 1, the other end thereof being connected to a wire 19 bymeans of a metal connecter 18 whose length is adjustable. The other endof the wire is passed over a wire sheave rotatably supported on theoutside of the base frame 2 and secured to the lower end of the movableframe 14 of the elevator 11. Thus, the chain 16 and wire 19 areconnected together in endless form through the movable frame 14. A motorM for driving the elevator 11 is mounted on the upper support frame 4and drives a shaft 24 of the sprockets 17 through a pair of pulleys,belt 22 and a reduction gear 23. A limit switch LS for givinginstructions to elevate and stop the elevator 11 and a limit switch LSfor initiating the operation of the pallet feed conveyor 6 are providedat the upper and lower ends of the guide bar 13 respectively and adaptedto be brought into contact with an actuating member 32 when the elevator11 reaches the upper limit and lower limit of its movement (see FIG. 1).

As indicated at A in FIG. 2, the articles on the pallet P are arrangedin ranks each including several articles and piled up in multi-layers.FIG. 3 shows in detail a flexible movable conveyor 25 for removing thearticle A from the pallet P one row after another. Referring to thefigure, the movable conveyor 25 includes a number of rollers 26 having apredetermined length and aranged in parallel. These rolles 26 areoperatively interconnected so as to be rotated in the same direction bymeans of sprockets 27 mounted on the opposite ends thereof and chains 21trained over the sprockets, each of the roller 26 further being securedat its opposite ends to the links of a pair of roller chains 28 spacedapart in parallel by a predetermined distance. The roller chains 28serve to move the movable conveyor 25 toward or away from articles Awhich have been brought to a predetermined position by the elevator l 1.Each of the roller chains 28 is trained, in inverted U- shape, over apair of sprockets 29 and 30 which are mounted on the upper support frame4 respectively at its front and rear ends. Two other chains 33 smallerthan the roller chains 28 are respectively reeved in U- form aroundpairs of sprockets 34 and 35 disposed at the front and rear of thesupport structure 1 at its lower portion, the opposite ends of thechains 33 being connected to the opposite ends of the roller chains 28respectively. Thus, both chains are disposed in endless mannerapproximately in square form. Two rotary shafts 36 and 37 carrying thesprockets 34 and 35 are mounted on the base frame 2 and one of theshafts is adapted to be moved forward and backward in horizontaldirection by tension means 38.

A reversible motor M for driving the movable conveyor 25 toward or awayfrom the articles A lifted to the predetermined position by the elevator11 rotates a drive shaft 39 to which the sprockets 29 are keyed by wayof a reduction gear 40, chain 41 and sprocket 42. Guide plates 43 forthe roller chains 28 and chains 33 are disposed at suitable positionsalong linear portions of the chains.

Means for scooping up the articles from the pallet P in frictionalcontact therewith is mounted at the front end of the movable conveyor25, namely at the end of the conveyor to be brought into proximity withthe articles A. The construction of the scooping means is illustreatedin detail in FIGS. 4 to 6. Referring to these drawings, the scoopingmeans 44 includes a plurality of upper endless belts 45 and lowerendless belts 46 which are spaced apart by a distance slightly greaterthan the height of the article A. The upper belts 45 serve to preventtumbling of the article A and are in the form of flat belt. The belts 45are passed around pulleys 47 and 48 in inclined position. The pulleys 47and 48 are mounted on shafts 49 and 50 supported on opposite brackets 51and 51 adapted for upward and downward movement. A drive sprocket 52 iskeyed to the shaft 49 at its end.

A screw rod 53 for adjusting the level of the bracket 51 is screwedvertically into a screw cylinder 51a at its base portion and the upperand lower ends of the screw rod 53 are rotatably supported by a supportframe 54, the arrangement being such that by turning the rod with aspanner or the like, the bracket 51 can be moved up or down. The supportframe 54 is provided at each side of the machine, and the lower end ofthe frame 54 is secured by suitable means to the inner side of anelongated link 55 which is longer than the other links included in theroller chain 28. The lower belts 46 which scoop up the articles A infrictional contact with one side face thereof are in the form of aplurality of V-belts. Several sets of the V-belts, each comprising threebelts, are reeved around pulleys 56 and 57 and spaced apart by apredetermined distance along the direction of the width at the forwardend of the movable conveyor 25. The belts 36 are positioned slightlyrearwardly of the upper belts 45 with their upper faces disposed at asmaller inclination than the under faces of the upper belts 45. Shafts58 and 59 carrying the pulleys 56 and 57 respectively keyed thereto arerotatably supported at their opposite ends on plates 60 disposed insidethe support frames 54 at their lower ends, the shaft 58 being providedat its one end with a sprocket 61 for driving the lower endless beltsand, at the other end, with a sprocket 62 for driving rollers of themovable conveyor 25 (see FIG. 6).

The sprocket 62 is operatively associated through a chain 63 with thesprocket 27 of one roller 26 at the forward end of the movable conveyor25 so as to drive the roller.

The upper belts 45 and lower belts 46 included in the scooping means 44are driven by a chain 65 in such direction as to transfer the articlesonto the movable conveyor 25 in the rear, the chain 65 being adapted tobe driven by a motor M always in one direction. The motor M, is fixedlymounted on the upper support frame 4 on one side close to its rear endand drives a rotary shaft 68 through a reduction gear 66 andsprocket-chain transmission means 67. The chain 65 is trained around asprocket 69 fixed to one end of the rotary shaft 68 and a sprocket 71 oftension means 70. The sprocket 71 is mounted on a distal end of apivotal arm 73 one end of which is pulled by a spring 72 so as to keepthe chain 65 taut. A sprocket 75 is keyed to one end of a shaft 74transversely and rotatably supported on the upper ends of the oppositesupport frame 54 and 54. The upper run of the chain 65 is reeved aroundidle sprockets 76 and 77 disposed at a lower opposite side portions ofthe frame 54, with the intermediate portion of the chain 65 trained overthe sprocket 75 in an inverted U-form. The sprocket 75 is driven in acounterclockwise direction. Rotatably supported on the bracket 51 on itsinner side is an idle sprocket 81 on which an intermediate portion ofthe lower run of the chain 65 is supported. Two sprockets 78 and 79 arekeyed to the shaft 74 at the other end thereof, one of the sprocketsbeing operatively connected by a chain 80 to the aforementioned sprocket61 for driving the lower belts, the other sprocket being associatedthrough a chain 84 with an idle sprocket 83 mounted on one end of ashaft 82 supported on the brackets 51 and 51. Part of the lower run ofthe chain 84 is passed over the sprocket 52 for driving the upper belts45, these sprockets thus being retained in operative relationship witheach other. Supported on the inner face of the support frame 54 are twoidle sprockets 85 and 86 which are associated with the chains 80 and 84respectively so as to guide the chains. A belt guiding plate 87 isdisposed transversely of the machine between the upper run and the lowerrun of the lower belt 46 and the oppposite ends of the guiding plate 87are secured to the lower ends of the opposite support frames 54. Guideplates 88 on the opposite sides serving as guide during depalletizingoperation are disposed to the front of the lower forward ends of thesupport frames 54 and project forwardly and outwardly in flaringfashion. A stop plate 89 for preventing the articles A from movingforwardly of and away from the scooping means 44 duringunloadingoperation is positioned ahead of the means 44. The stop plate89 is supported at its opposite ends on the upper ends of pivot arms 90.Piston rods 92 of air cylinders 91 are pivotally connected, at theirdistal ends, to the stop plate 89 on its face opposite to the face to bebrought into contact with the articles A. During the operation, air issupplied to the air cylinders all the time to retain the piston rods 92in extended position.

A stopper 93 shown in FIG. 7 is positioned slightly rearwardly of thedownwardly bent rear portion of the movable conveyor 25. At thisposition, the articles A are transferred from the movable conveyor 25 toa delivery conveyor 101 shown in FIG. 1. The stopper 93 is in the formof a slender roller rotatably supported at its ends on opposite pivotalplates 94. During operation, the stopper 93 is positioned above thearticle carrying plane of the movable conveyor 25, whereas when thearticles are transferred on to the delivery conveyor 101, it isretracted downward to open the passage. An air cylinder 95 is providedwith a piston rod 56 whose distal end is connected to a portion of oneof the pivotal plate 94, the stopper 93 thereby being adpated for upwardand downward movements described above.

An article delivery roller Q7 provided with a rubber lining istransversely positioned between the opposite pivotal plates 94 andsupported by the plates at the center of the pivotal movement. Theroller 97 is driven in the direction of transport of the articles by amotor M through a chain 98 and a sprocket 99. Another delivery roller64, positioned ahead of the roller 97, is operatively associatedtherewith through a chain and sprocket mechanism 100.

Referring to FIG. 1, the delivery conveyor 101 is positioned to the rearof and at a right angle with the movable conveyor 25 and supported atits opposite ends by a plurality of legs 102. A great number of rollers103 providing a delivery path are operatively connected together by asprocket HM mounted at one end of each roller and a chain trained aroundeach group of sprockets 104 which group comprises a plurality of thesprockets. Through chain and sprocket transmission means 106 and 107,the torque of two motors M and M is delivered to two suitable rollersamong the rollers 103. Thus all of the rollers 103 are driven at thesame time in operative relationship. Provided on the delivery conveyor101 are a plurality of guide members 108 for forming a path fortransporting the articles A in a single row. Further mounted at the rearend of the conveyor 101 on one side thereof is a guide plate 109 forbringing the articles to a position longitudinally parallel to thedirection of transport which articles have been sent forward with theirlengthes positioned parallel or transverse to the direction of travel.

Limit switches LS and LS. are disposed at the positions of forward andbackward ends of movement of the conveyor 25, on the upper face of theupper support frame 4 at its one side. When the conveyor 25 reaches theterminal position of its forward travel, the switch L8,, is actuatedupon contact with an actuating member provided at the front end of themovable conveyor 25 and de-energizes the motor M to stop the forwardmovement of the movable conveyor 25, while acmating the air cylinder tolower the stopper 93. The other limit switch LS is actuated when themovable conveyor 25 reaches the terminal position of its backwardmovement, the limit switch LS thus providing an electrical instructionfor halting the backward movement of the movable conveyor 25. The limitswitch LS, also energizes the motor M and provides an instruction tomove up the elevator 11. A limit switch L8,, is positioned slightlyahead of a stop plate 89 for preventing forward movement of the articlesA. If the articles are not smoothly scooped up due to an accident andthe stop plate 89 is forced to move against the pneumatic pressure ofthe air cylinders 91, the stop plate 89 comes into contact with thelimit switch LS, to stop the movement of the conveyor 25 completely.

Photoelectric tube switches Pl-l and PH each comprising a projector andreceiver are so disposed as to project upwardly from the upper supportframe 4, the positions of the switches PH;, and PH, being such that whenthe elevator 11 moves up the uppermost layer of the articles A about9/10 the height of the articles above the level of the forward ends ofthe lower belts 46 for scooping, the beams will be intercepted by thearticles. When the beams from the switches PH; and PH, are thusintercepted, the electrical instructions thereby produced act to haltthe elevation of the elevator 11 while initiating the movable conveyor25 into forward movement. Another photo-electric tube switch PH, ismounted on the upper support frame 4 at a position close to its rearend, and when the articles A are present on the movable conveyor 25 thebeam from the switch PH, is intercepted. When the beam becomes no longerintercepted, the switch PH, gives an instruction to the conveyor 25 forretraction. Other two photoelectric tube switches PH and PH provideinstructions to actuate the air cylinder 95 so as to initiate thestopper 93 into upward and downward movements. The switches PH and PH,are mounted on a frame at the front and of the delivery conveyor 101 andso posi-- tioned that the beam thereof will be intercepted by thearticles when they are present on the delivery conveyor 25 at a positionjust behind the movable conveyor 25 Now a complete cycle of theoperation for removing articles from a pallet will be explained below.

The pallet P loaded with articles A in layers is carried by the feedconveyor 6 onto the elevator 11 in the interior of the support structureI. When the front end of the load intercepts the beam from thephotoelectric tube switch PH the motor M is thereby halted to stop themovement of rollers of the feed conveyor 6. At the same time, the motorM, for driving the elevator 11 is initiated into rotation in a positivedirection to raise the elevator 11. At this time, the movable conveyor25 is in a retracted position and the upper portion of the supportstructure ll is left open. Accordingly, the uppermost layer of thearticles A, when brought up to a predetermined level above the uppersupport frame 4, intercepts the beams from the photoelectric tubeswitches Pit and PH whereby the upward movement of the elevator 11 isstopped. At the same time, the motor M for driving the movable conveyor25 is energized for rotation in a positive direction, causing the rollerchains 28 to run rightward as seen in FIG. 3 to advance the conveyor 25toward the articles A. During this time, the upper belts 45, lower belts46 and rollers 26 are driven in the directions indicated by arrows inthe figure due to the rotation of the motor M and the resultantoperation of the chain 65. When the front ends of the lower belts 46 arebrought into contact with the first row of the articles A in theuppermost layer, the belts 46 as shown in FIG. fl raise the articles infrictional contact therewith due to the rotation of the belts and carryup the articles A on the upper surfaces thereof as they move forward.During this operation, the articles A are prevented from moving awayfrom the scoop means 44 since the last row of the articles in the layerto be removed is in abutting contact with the stop plate 89, thescooping operation by the lower belts 46 thus being insured. if thebelts 46 fail to scoop up the articles A for one reason or another, thestop plate 89 will be pushed forward against the neumatic pressurewithin the air cylinders 91, with the results that the stop plate comesinto contact with the limit switch L8,, to stop all of the movements ofthe conveyor 25. The rows of articles A which have been depalletized onerow after another as the lower belts 46 advance are carried rearward bythe rollers 26 in rotation. During this operation, the upper belts 45act in the following manner to prevent the articles A from tumbling.Suppose articles A, for instance, bottled-packed boxes are carriedupward in an inclined position on the lower endless belts 86. if thefront end of a box falls between the bottles in the underlying layers,the box will be tumbled as the lower belts 46 advance. However, theupper belts 45 disposed above and slightly ahead of the lower belts 46engage the upper end of the inclined articles A and drive the article Abackward, so that the article can be transferred onto the movableconveyor 25. When the articles are scooped up in normal position, theupper ends of the bottles, namely the upper ends of the articles A passslightly below the upper belts 45 without coming into contact therewith.

When the articles A are transferred onto the movable conveyor 25, thestopper 93 in the rear is positioned above the conveyor plane of thegroup of rollers 26. The articles A sent rearward on the conveyor 25 areblocked by the stopper 93 one after another and retained on the conveyor25. When the articles A in one layer have all been depalletized and theconveyor 25 reaches the terminal position of its forward travel 25, thelimit switch LS is actuated, whereby the motor M is stopped, the pistonrod 96 of the air cylinder 95 being retracted simultaneously therewithto cause the pivotal plates 943 to move backward pivotally. Thus thestopper 93 is withdrawn downward from the plane of the rollers 26. As aresult, the articles A are transferred onto the delivery conveyor Millone row after another from the foremost position. Since the transferrollers 97 and 64 are driven at a higher velocity than the rollers 26 ofthe movable conveyor 25, the article A sent out onto the deliveryconveyor 101 will be spaced apart from the following article A, with theresult that when a row of articles A is transferred onto the deliveryconveyor 101 to intercept the beams from the photoelectric switches PHand PH the instructions produced by the switch cause the stopper 93 toelevate again. While the following rows of articles A are blocked by thestopper, the first row of the articles A is carried in the direction ofdelivery by the conveyor 101. When the beams from the photoelectric tubeswitches PH and PH, become no longer intercepted, the stopper 93 islowered again, whereupon the second row of the articles A is sent outonto the delivery conveyor 101 in like manner.

Thus, when all the articles A on the movable conveyor 25 have been sentout, interception of the beam from the photoelectric switch PH, isrelived, whereupon the motor M is rotated in a direction opposite to theprevious direction to retract the movable conveyor 25. In thisoperation, the rollers 26 and upper and lower belts 45, 46 are sloweddown due to the relationship with the running direction of the chain andare therefore driven at a low velocity. As a result noises areminimized. The limit switch LS actuated when the movable conveyor 25reaches the extreme position of its backward travel, stops the motor Mto halt the retraction of the movable conveyor 25 and at the same timeinitiates the motor M into operation to lift the elevator 11. After thearticles A in the uppermost layer intercept the photoelectric switchesPR and PH.,, the subsequent operations of the machine will be carriedout in the same manner as described above.

Thus the articles A in the upper position are removed successively fromthe elevator 11 onto the movable conveyor 25. Upon the elevator 11reaching the extreme end of its upward movement, the limit switch LS, isactuated, whereby the motor M, is momentarily stopped. The motor M willthen be rotated in the reverse direction to lower the elevator 11 untilthe elevator reaches the end of its downward travel, whereupon the limitswitch LS is actuated. The instruction given by the switch then bringsthe motor M to a halt to stop the downward movement of the elevator 11.Simultaneously with this, the motor M for the feed conveyor 6 isenergized to bring the articles A on another pallet P onto the elevator11.

As apparent from the description above, the present invention provides anovel and efficient machine by which the articles loaded on pallets areremoved from the uppermost position one row after another withouttumbling the articles.

I claim:

1. An unloading machine comprising a movable conveyor supported on asupport structure and including a number of rollers adapted to be movedreciprocally between a front position and a rear position, articlescooping means mounted at the front end of said conveyor, drive meansfor moving said conveyor toward and away from articles together withsaid scooping means and means for preventing said articles from movingaway from said scooping means, said article scooping means beingprovided with a rotary body for lifting said articles in frictionalcontact therewith and means disposed above said rotary body forpreventing said articles from tumbling, each of said rotary body forlifting said articles and said means for preventing said articles fromtumbling comprising at least one endless belt, both of said belts beingadapted to be driven in such directions as to send said articles towardthe rear of said movable conveyor.

2. An article unloading machine comprising a support structure, amovable conveyor including a number of rollers reciprocally movable inhorizontal direction on said support structure, means for supportingarticles in the path of movement of said conveyor, a plurality of lowerendless belts disposed side by side along the width of front end of saidmovable conveyor, at least one upper endless belt disposed above saidlower endless belts in facing relationship therewith and spaced aparttherefrom by a distance for passing said articles, conveyor drive meansfor reciprocating said movable conveyor along said path and bringingsaid lower endless belts into contact with said articles, a motorfixedly mounted on said support structure at its side portion, endlesschains to be driven by said motor and trained over a distance longerthan the length of path of said movable conveyor, means for driving saidupper and lower endless belts and rollers of said movable conveyor insuch directions as to scoop up said articles and send out the samebackward when said chains are driven, and means for preventing saidarticles from moving away from said lower endless belts, said upper andlower endless belts and said rollers being adapted to be driven at alower velocity when said movable conveyor is moved backward than when itis advanced.

WI 9 I6 I i

1. An unloading machine comprising a movable conveyor supported on asupport structure and including a number of rollers adapted to be movedreciprocally between a front position and a rear position, articlescooping means mounted at the front end of said conveyor, drive meansfor moving said conveyor toward and away from articles together withsaid scooping means and means for preventing said articles from movingaway from said scooping means, said article scooping means beingprovided with a rotary body for lifting said articles in frictionalcontact therewith and means disposed above said rotary body forpreventing said articles from tumbling, each of said rotary body forlifting said articles and said means for preventing said articles fromtumbling comprising at least one endless belt, both of said belts beingadapted to be driven in such directions as to send said articles towardthe rear of said movable conveyor.
 2. An article unloading machinecomprising a support structure, a movable conveyor including a number ofrollers reciprocally movable in horizontal direction on said supportstructure, means for supporting articles in the path of movement of saidconveyor, a plurality of lower endless belts disposed side by side alongthe width of front end of said movable conveyor, at least one upperendless belt disposed above said lower endless belts in facingrelationship therewith and spaced apart therefrom by a distance forpassing said articles, conveyor drive means for reciprocating saidmovable conveyor along said path and bringing said lower endless beltsinto contact with said articles, a motor fixedly mounted on said supportstructure at its side portion, endless chains to be driven by said motorand trained over a distance longer than the length of path of saidmovable conveyor, means for driving said upper and lower endless beltsand rollers of said movable conveyor in such directions as to scoop upsaid articles and send out the same backward when said chains aredriven, and means for preventing said articles from moving away fromsaid lower endless belts, said upper and lower endless belts and saidrollers being adapted to be driven at a lower velocity when said movableconveyor is moved backward than when it is advanced.